The design principle, way and main advance of breeding system to improve simultaneously cotton yield, fiber quality, disease resistance and so on were elaborated in this thesis. According to the principle of both the additive effects and recombination of the favourable genes and complementary action among many characters of the hybridization parents to this breeding system, and through the cross many times among a lot of parents and the oriented selection, these characters would get improved simultaneously by our breeding manipulation. This breeding system would provide a new method and theory guide to cultivate outstanding cotton variety with good comprehensive traits